The Bayou Jumper

Un Récepteur à Réaction - Le Sauteur de Bayou Cajun French for "The Bayou Jumper" (a play on "Ocean Hopper" and homage to the French heritage in Louisiana) A regenerative receiver designed for the CW segment of the 40 meter ham band Based on a design by Charles Kitchin, N1TEV Adapted by Jim Giammanco, N5IB revised 20 Aug 2016 Yahoo Group:

https://groups.yahoo.com/neo/groups/Bayou_Regen_Rx/info

Tuning range approximately 120 to 150 kHz – enough to cover from a portion of the Extra Class CW band into the old “Novice Band.” One knob tuning – no bandset/bandspread needed. Only one toroid to wind. Varactor tuning employing readily available Schottky diodes as varactor diodes. Regeneration control also employs a “Schottky varactor” as the throttle capacitor. Use of potentiometers controlling only the varactor DC bias for tuning and regeneration means the controls are not “hot” with RF, so “hand effect” detuning is minimized. Only a few feet of wire needed as an antenna. Optional RF attenuator control, which is useful when employed with full-scale antennas. Optional receiver audio muting for use with a transmitter. Robust headphone audio, and will drive a small speaker with modest volume. Best operated from 12 V supply, but will operate on a 9 V battery. Current drain about 20 mA. Should be adaptable for 80, or 30 meters. Possible companion receiver for a ColorBurst transmitter. Rev 1.9 schematic has some preliminary notes for 30 meters. Shown at right is the prototype, housed in a wood box obtained from Hobby Lobby. The panel is made from copper clad PCB stock. A frequency calibration card is inside the top cover.

TOP COPPER – approximately actual size – versions 1.74 (OK for 1.75), and 1.79

BOTTOM COPPER – approximately actual size – versions 1.74 (OK for 1.75), and 1.79

Prototype rev1.61 PCB

40 meter Kitchin-style Regenerative Receiver Bill of Materials for rev1.72, 1.75, and 1.79 schematics and rev1.70, 1.72, 1.74, 1.75 and 1.79 PCBs ID

Description

Vendor Catalog Number

7

C1 C2 C7 C11 C12 C17 C22

0.01 uF 50V ceramic X7R .2" LS

Mouser 81-RDER71H103K0M1H3A

3

C15, C19 C25

0.1 uF 50V ceramic X7R .2” LS

Mouser 81-RDER71H104K0K103B

1

C8

1000 pF 50V 5% C0G ceramic .2” LS

Mouser 81-RDE5C1H102J0K1H3B

1

C16

.047 uF 50V ceramic .2" LS

Mouser 581-SR211C473KAR

1

C4



1

C26

47 pF 50V 5% C0G ceramic .2" LS


1

C18



1

C20a

120 pF 50V 5% C0G ceramic .2” LS polystyrene

1

C20b

22 pF 50V 5% C0G ceramic .2" LS


1

C5

0.22 uF 10% X7R 50V ceramic .2” LS

Mouser 594-K224K20X7RF53H5

2

C10 C24

0.022 uF 50V 10% X7R ceramic .2” LS

Mouser 594-K223K15X7RF53L2

1

C29

0.0047 uF 50V 10% ceramic or mylar .2" LS

Mouser 594-K472K15X7RF53L2

1

C6

470 uF 25V electrolytic 5mm LS

Mouser 140-REA471M1EBK1012P

2

C9 C27

4.7 uF 25V electrolytic 2mm LS

Mouser 140-REA4R7M1EBK0511P

2

C3 C13


Mouser 140-REA100M1EBK0511P

1

C14

100 uF 25V electrolytic 2.5mm LS

Mouser 140-RGA101M1EBK0611G

1

C28


Mouser 140-RGA470M1EBK0511

1

C21

20 pF trimmer

eBay item # 250847960661, $3.58 for 20

1

C23

50 pF trimmer

Kits and Parts #96, bag of 12 for $5 or eBay # 390327607132, $3.58 for 20

3

D1 D2 D3 D4 (D4 optional)

1N5819 Schottky diode

Mouser 821-1N5819

1

L1

T68-2 or T68-6 ot T68-7 toroid core

Kits and Parts #198 (T68-2) or #201 (T68-6)

1

L4

1 mH molded RF choke

Mouser 434-23-102-01

1

Q1

2N2222 or 2N2222A NPN BJT

Kits and Parts #112, bag of 50

1

Q2

MPF102 or J-310 N-JFET

Arrow Electronics J310G

1

Q3

2N3904, 2N2222, or 2N4401 NPN BJT

Mouser 512-2N3904BU

2

R1 R3

2.7 K ¼ W, 5%, carbon film

Mouser 291-2.7K-RC

1

R2

1 M ¼ W, 5%, carbon film

Mouser 291-1M-RC

1

R4


Mouser 291-5.6K-RC

1

R5 (for rev1.79: R5a, R5b, R5c)

R5 or R5a = 33 K ¼ W, 5%, carbon film (R5b, R5c TBA)

Mouser 291-33K-RC

2

R7, R18

10 Ω ¼ W, 5%, carbon film

Mouser 291-10-RC

1

R19

15 K ¼ W, 5%, carbon film

Mouser 291-15K-RC

1

R17


Mouser 291-1K-RC

2

R9 R11


Mouser 291-470K-RC

1

R12


Mouser 291-3.9K-RC

1

R13

390 Ω ¼ W, 5%, carbon film

Mouser 291-390-RC

1

R14


Mouser 291-390K-RC

2

SW1 SW2

SPST (SW1 may be part of R6)

Marlin P Jones #25006 SW

1

U1

LM386-3 or -4

Kits and Parts #102

U1

alternate source

Mouser 926-LM386N-4/NOPB

Quant

or, optionally,


1

U2

LM78L06

Mouser 512-KA78L06AZTA

1

R15

1 K linear pot

Mouser 58-P110KV11F25BR1K

1

R6

10 K audio pot (switch optional)

Kits and Parts #316, bag of 3 for $3

2

R8 R10

50 K linear pot

Mouser 858-P110KV10F20BR50K

1

PCB1

Etched Circuit Board

N5IB

1

Antenna

BNC chassis connector

Marlin P Jones #20507 RC

1

Power

2.1 x 5.5 mm DC power connector

Marlin P Jones18549 PL

1

Audio Out

stereo headphone jack

Kits and Parts #313, bag of 4 for $4

alternate source

Marlin P Jones #25515 PL

#24 enameled wire

Kits and Parts #134 10 ft for $1.50

1

Wire

Circuit information and build notes Tuning range and bandspreading – If the total tuning range is kept to 150 kHz or less, a band spread or finetuning control is not needed. Tuning will be slow enough for both CW and SSB signals. The tuning range is primarily controlled by C18 and R5. The smaller C18 is made, the smaller will be the effective change in capacitance due to D3, hence the smaller will be the tuning range. Values of C18 between 33 pF and 100 pF have been tried. Conversely, as R5 is made smaller, a greater range of bias voltage is available on D3, so the tuning range will be increased. R5 should not be smaller than about 10K, to avoid bringing D3 too close to zero bias. R8 should be connected so that the voltage at its wiper increases with clockwise rotation. This will have the effect of dial frequency increasing with clockwise rotation of R11. Regeneration range – C23, in parallel with the series combination of C26 and D2, act as the traditional throttling capacitor to control the amount of regeneration. Larger capacitance means increased regeneration. In much the same way as in the main tuning control, C26 and R16 (if R16 is actually installed) determine the range of capacitance that can be accomplished by varying the bias on D2. The object is to adjust C23, so that when the receiver is tuned to its lowest frequency, the detector just begins to oscillate when R11 is advanced about one-fourth to one-third of its range. R11 should be connected so that the voltage at its wiper decreases with clockwise rotation. This will have the effect of regeneration increasing with clockwise rotation of R11. Tuning and regeneration capacitor options – It is quite possible to omit the tuning diodes D2 and D3 and use conventional variable capacitors, either air-type or polyvaricon. In that case the associated potentiometers, bias resistors, and bypass capacitors are omitted (R5, R8, R9, C11, C17 for tuning, R10, R11, R16, C22, R11 for regeneration) The variable capacitors could be installed at the locations of D3 (tuning) and D2 (regeneration). Extra pads are provided on the circuit board to allow padding with small values of fixed capacitors to tweak the tuning and regeneration ranges. Pads are provided at C20 to accommodate larger capacitors, such as polystyrene or mica parts. It is possible to try out different fixed capacitor values without soldering. Just insert the part so that it makes contact with the pads.

Audio gain – If it is anticipated that the receiver will be used only with headphones, emitter bypass capacitor C27 can be omitted and headphone volume will be quite adequate. Adding C27 will increase the gain of the audio pre-amplifier, which may help when driving a small speaker. Keep in mind that the LM386 audio output stage is not intended to give “room-filling” volume. Shorting the LPF pinheader will provide some additional high frequency roll-off that will help when listening to CW signals. A 15K resistor in series with a 0.005 µF capacitor, tacked on between pins 1 and 5 of the LM386, can help suppress some of the high frequencies. Strong signals / big antennas – Regenerative detectors are usually very sensitive, but prone to bad behavior in the presence of strong signals. R15 acts as an input attenuator and will help. The number of turns on the input coupling link is also important. When a full sized antenna is used, two, or even just one turn will be enough. If, though, the receiver is to be used with just a few feet of wire for an antenna, adding two or three turns may be advisable. Temperature stability – When installed in an enclosed cabinet, receiver stability is quite adequate. The tuning and regenerating controls are at DC levels only, with no RF present. So hand effects are minimal. The circuit board should be behind a metal panel to avoid detuning. The prototype pictured used PC board stock for the panel, and the inside of the wood box is lines with aluminum foil tape – the sort used to seal heating ducts. There are a couple of experiments that might yield even better stability. Changing the tank inductor core to a T68-7 is one idea. The -7 iron powder formulation has a lower temperature coefficient than the -2 mix. In fact, if a portion of the tank capacitance is implemented with a polystyrene capacitor there may be even more improvement. The temperature coefficient of the polystyrene cap is opposite that of the iron powder, so the two will offset somewhat. Perhaps implementing C20 with 50% of the value in NP0/C0G and the other 50% polystyrene would be a good starting point. Extra pads are provided adjacent to the C20 position. Use with a transmitter – The receiver is certainly sensitive and stable enough to use to make real QSOs. But some form of receiver muting will be essential, as the strong RF environment near a transmitter will drive the detector into apoplexy. Grounding of the input (right at the R15 side of C1 is probably better than at the antenna jack) is certainly needed, then muting of the audio amplifier by connecting pin 7 of the LM386 to either V+ or ground should also be done. The smaller R17 is made, the more “solid” the muting becomes. A value of 1K is a good starting point. There are slight differences in the level of muting depending on whether the connection is to V+ or to ground. The MUTE pinheader allows either option. Winding sense for L1 – The relative phase of the tank and tickler windings must be correct in order for the detector to oscillate. Refer to the photograph at right for the correct direction of each winding. Disregard the number of turns pictured. Only the direction is important. The phase of the input link is not critical, but the direction pictured will allow the leads to match the PCB pad locations.

INPUT

TICKLER

TANK

20 August 2015 Sauteur de Bayou Regenerative Receiver PC boards

BUILDER ALERT #1 Applies to PC boards rev1.61 top side

The yellow-circled pad should NOT be grounded to the top side ground plane. Cut the three small grounding traces with an X-Acto blade, or use a small drill bit (3/32” is best) – fingertwirled – to break the connection between the through-plating and the top side pad and ground plane.

bottom side

The yellow-circled pad has a tooclose clearance to the bottom side ground plane, but it will be OK to leave it that way. Just take care not to create a solder bridge.

BUILDER ALERT #2 Applies to rev1.70 and early (5 Aug 2015) rev1.72 PC boards (has been fixed in later rev1.72 & 1.74 boards)

The yellow-circled pads should NOT be grounded to the top side ground plane. Cut the two or three small grounding traces with an X-Acto blade, or use a small drill bit (3/32” is best) – finger-twirled – to break the connection between the through-plating and the top side pad and ground plane.

The yellow-circled pads have a too-close clearance to the bottom side ground plane, but it will be OK to leave them that way. Just take care not to create solder bridges.